Diseased or otherwise deficient heart valves can be repaired or replaced using a variety of different types of heart valve surgeries. One general type of heart valve surgery involves an open-heart surgical procedure that is conducted under general anesthesia, during which the heart is stopped and a heart-lung bypass machine controls blood flow. This type of valve surgery is highly invasive and exposes the patient to a number of potential risks, such as infection, stroke, renal failure, and adverse effects associated with use of the heart-lung machine, for example. Due to the drawbacks of open-heart surgical procedures, there has been an increased interest in minimally invasive and percutaneous replacement of cardiac valves. Such surgical techniques involve making a relatively small opening in the skin of the patient into which a valve assembly is inserted and delivered to the heart via a delivery device similar to a catheter. This technique is often preferable to more invasive forms of surgery, such as the open-heart surgical procedure described above.
Various types and configurations of prosthetic heart valves are used in percutaneous valve procedures to replace diseased natural human heart valves. The actual shape and configuration of any particular prosthetic heart valve is dependent to some extent upon the valve being replaced (i.e., mitral valve, tricuspid valve, aortic valve, or pulmonary valve). In general, prosthetic heart valve designs attempt to replicate the function of the valve being replaced and thus will include valve leaflet-like structures used with either bioprostheses or mechanical heart valve prostheses. If bioprostheses are selected, the replacement valves may include a valved vascular segment that is mounted in some manner within an expandable stent frame to make a valved stent. In order to prepare such a valve for percutaneous implantation, one type of valved stem can be initially provided in an expanded or uncrimped condition, then crimped or compressed around a balloon portion of a catheter until it is as close to the diameter of the catheter as possible. In other percutaneous implantation systems, the stem of the valved stent can be made of a self-expanding-material. In either case, the shape of the stent frame in its expanded condition will typically be at least slightly different than the shape of the implantation site, therefore creating the potential for gaps or spaces between the stent frame and the implantation site that allow for paravalvular leakage. For one example, placing a circular aortic stem in an aortic annulus that has a non-circular shape may result in a gap between the stem and the aortic wall, thereby creating the potential for paravalvular leakage.
With an increasing number of valve replacements being performed using a percutaneous or transcatheter valve delivery approach, it is desirable to provide methods and devices for repairing paravalvular leakage, particularly those that can allow for repairing the leaks in a percutaneous manner. However, it is also desirable to provide methods and devices for repairing paravalvular leakage for valves that have been surgically implanted.